KERNEL_VERSION=whatever
EXTRAMODULES=whatever

dep_extr_mod(){
if [ $EXTRAMODULES != null ]; then
    depmod $(cat usr/lib/modules/$EXTRAMODULES/version)
else
    depmod $KERNEL_VERSION
fi
}

post_install() {
    dep_extr_mod
}

post_upgrade() {
    dep_extr_mod
}

post_remove() {
    dep_extr_mod
}
